Convective and Stratiform Components of Tropical Cloud Clusters in Determining Radar Adjusted Satellite Rainfall during the TOGA-COARE IOP
Convective and Stratiform Components of Tropical Cloud Clusters in Determining Radar Adjusted Satellite Rainfall during the TOGA-COARE IOP
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热带云团的对流和层状成分在确定 TOGA-COARE IOP 期间雷达调整的卫星降雨量中的作用
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发表时间：
1998
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通讯作者：
K. Kikuchi
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作者：
N. Islam;H. Uyeda;Osamu Kikuchi;K. Kikuchi
本文描述了在TOGA-COARE lOP期间，利用雷达和GMS-IR每小时TBB数据对对流和层状降水的估计。将CST （Convective Stratiform Technique）算法应用于TOGA-COARE对流，对分析区（5N-5S, 150E-170E）的GMS-IR数据进行分析，并与雷达分析结果进行比较。在确定了“启夫丸”雷达40 dBZ的阈值反射率后，利用雷达图像对MCSs降下的对流和层状降水进行了识别和量化。定义的阈值成功地分离了对流云和层状云成分。利用Keifu Maru雷达数据赋值的雨率，对卫星数据进行CST分析，两者分析结果吻合较好。嵌入区域的对流云和层状云分量分别约占25%和75%。对流的降水量为62%（雷达）和64% (CST)，层状的降水量为38%（雷达）和36% （CST）。这些结果与GATE的结果非常一致。用云长(L)参数客观分析了热带云的三个阶段。长度范围划分为：(1)形成性：L<100 km；(2)成熟：100<L<330 km；(3)耗散：L>330 km。在有限雷达覆盖范围内的雷达分析与CST结果非常吻合后，将CST应用于热带云和云团的整个生命历史。CST能够提取定义云的可降水量部分（T BB =230 K）： 56%的云可降水量，44%的云不可降水量。雷达确定的地表降水占CST确定的可降水量的90%，这要求雷达和CST的结果有很强的一致性。•目前隶属：孟加拉国工程技术大学物理系，dhaka iooo, Bangladesh 266 Md. N. Islam等。
This paper describes the estimation of convective and stratiform precipitations from both radar and GMS-IR hourly TBB data during the TOGA-COARE lOP. The CST (Convective Stratiform Technique) algorithm was adapted for TOGA-COARE convection to analyze GMS-IR data in the analysis area (5N-5S, 150E-170E) and compare the results with those of radar analysis. The convective and stratiform precipitations falling from the MCSs were identified and quantified by radar image after defining a threshold reflectivity of 40 dBZ for Keifu Maru radar. The defined threshold successfully separated the convective and stratiform cloud components. Using the rain rates assigned from Keifu Maru radar data, the CST analysis was performed on the satellite data to obtain good agreement between the results of the two analyses. The convective and stratiform cloud components embedded regions were shown to be about 25% and 75% respectively. The rainfall amounts were calculated at 62% (radar) and 64% (CST) for convective, and 38% (radar) and 36% (CST) for stratiform. These results are strongly consistent with the results of GATE. Three stages of the tropical clouds were objectively analyzed by using a parameter named length of cloud (L). The length ranges were separated as (1) formative: L<100 km; (2) mature: 100<L<330 km; and (3) dissipating: L>330 km. After obtaining a strong agreement with the radar analysis over a limited coverage of radar, the CST was applied to the entire life history of the tropical clouds and cloud clusters. The CST enabled the extraction of the precipitable portion of the defined cloud (by T BB =230 K): 56% of the cloud was precipitable while 44% was nonprecipitable. The surface precipitation determined by radar was 90% of the precipitable portion determined by the CST which demands a strong agreement between the results of radar and CST . • Present affiliation: Department of Physics, Bangladesh University of Engineering and Technology, Dhaka-IOOO, Bangladesh 266 Md. N. Islam et al.